The present invention relates generally to a positioning device; specifically a device with magnetic attaching power that can be used to position metal work pieces for ease of being worked/operated upon.
Magnetic aligning or positioning tools are widely used for the positioning or aligning of metal work pieces. These tools are mostly made of a single magnetic piece, or two (2) magnetic pieces put together in a certain configuration. Such tools provide a fixed-angle (such as 90-degree fix angle) or adjustable-angle device made from two magnetic pieces hinged together by an axle-connection.
A prior art example of Eclipse Tools' heavy duty variable clamp is provided in FIG. 1, containing the following features: magnetic pieces 11 and 12 are connectably linked by connection axle 3; magnetic plates 121 are embedded to (but not completely submerged into) a surface of magnetic pieces 11/12; positioning arm pieces 112 and 122 are respectively extended from the magnetic pieces 11 and 12, where a groove-slot 1221 is formed on positioning arm piece 122, and where a locking bolt 61 is connected to arm piece 112 (and going through the groove-slot 1221 on arm piece 122), with a locking nut 62 on the other side of arm piece 122 that serves to tighten relative position/angle of arm pieces 112 and 122, after an angle has been selected, as between the work pieces in contact with the magnetic plates 121.
The disadvantages of such prior art device include: in the case where work pieces are big or heavy, locking bolts 61 and nuts 62 tend to loose the tightness as between the two arm pieces 112 and 122, due to continuous weight applied onto the positioning device, resulting in the change of the selected angle. Moreover, when such prior art device is used on work pieces with varied and changing angles, it is both time-consuming and inefficient to set up the positioning/alignment for the work piece angles that are frequently used in the industry. Such disadvantages further lead to random errors when the selection and setting of the frequent angles cannot be obtained quickly.